Optics: measuring and testing – For optical fiber or waveguide inspection
Patent
1998-05-04
2000-02-08
Font, Frank G.
Optics: measuring and testing
For optical fiber or waveguide inspection
356 43, G01N 2188
Patent
active
060233257
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
In the case of lathe bars and like tool holder rods used in machine tools, vibrations and bending will occur as the machine tool is at work. These vibrations and deflections of the tool holder rods can be particularly troublesome, especially when the rods have long lengths.
One problem in this regard resides in the vibrations, and particularly sympathetic (resonance) vibrations that occur in the system, particularly between the driving end of the tool holder shaft and a cutting bit carried by the tool holder. For instance, the power alternating effect between workpiece and cutting bit can induce bending, twisting and/or axial compression of the tool holder shaft. The shaft can also be induced into some form of vibratory state, causing the bit to vibrate and thereby generate a corresponding surface state of the workpiece.
NO-C-172 677, for instance, teaches a method of minimizing vibrations with the aid of a vibration damping device on a tool holder rod.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a tool holder rod that is provided with sensing or detecting devices that are effective in sensing or detecting at least bending of the tool holder rod and preferably also twisting of the rod and/or changes in axial lengths thereof, so as to enable the actual position of the cutting bit relative to the known attachment position of the tool holder rod to be detected when the tool is at work, so that the machine tool parameters can be adjusted such that the bit will take the intended position and produce the desired working surface on the workpieces irrespective of whether or not the tool holder rod is twisted and/or bent or increases in length as the machine tool is at work.
Another object of the invention is to detect time-wise variations in bending, twisting and/or length changes of the tool holder shaft, so as to enable the operating parameters to be changed in a manner to keep bit vibrations within acceptable and chosen limits. This enables the skilled person to vary the operating parameters in a manner to avoid the resonance phenomenon.
Another object of the invention is to provide means for sensing the bit temperature when the machine tool is at work, so as to obtain an indication of the state of the cutting bit and therewith enable a cutting bit to be changed before a breakdown occurs; the beginning of a breakdown can often be forecast as a result of a specific temperature development.
In accordance with the invention, bending and bending variations of the tool holder shaft are measured with the aid of an optical fibre section mounted in or on the shaft at a distance from its neutral bending line, preferably close to the outer surface of the shaft. The optical fibre section is mounted in the longitudinal direction of the shaft. As the shaft bends, the optical fibre section will therefore be subjected to a change in length representative of the bend in an axial plane that is placed under tension by the optical fibre section and the shaft axis. By shaft ais is meant the shaft neutral bending line, i.e. the centres of gravity of the cross-sectional areas of the shaft. It is then possible to evaluate bending of the shaft, by calculating the physical change in distance between two partial reflection means (e.g. grids) which are mutually spaced the optical fibre section, wherein, in accordance with the invention, an optical measurement is made such that the measuring result will be primarily comprised of the optical change in distance between said partial reflection means. It is important to note in this regard that this optical change in distance does not only correspond to the change in physical distance, but is also influenced by the effect of the physical elongation on the optical properties of the fibre, such as its refractive index. Because the optical fibre section has mutually spaced partial reflection means, it is possible to detect interferometrically changes in length of the optical fibre section between the reflection means as a result of b
REFERENCES:
patent: 4151747 (1979-05-01), Gottlieb et al.
patent: 4295739 (1981-10-01), Meltz et al.
patent: 4745908 (1988-05-01), Wardle
Ericsson Claes
Sahlgren Bengt
Stubbe Raoul
Font Frank G.
Nguyen Tu T.
Reflex Instrument AB
LandOfFree
Arrangement for sensing elastic deformation in a tool stem in a does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Arrangement for sensing elastic deformation in a tool stem in a , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Arrangement for sensing elastic deformation in a tool stem in a will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1685244